Model Context Protocol Publishes 2026-07-28 Specification with Breaking Transport Layer Changes
The MCP specification version 2026 07 28 was officially published on July 28, 2026 as the largest breaking revision since launch, transitioning the protocol fr…
Published on MyPrivateClaw
Jul 29, 2026, 2:58 AM UTC
Coverage date
Jul 28, 2026
Last updated
Jul 31, 2026, 6:28 AM UTC
News summary
The 2026 07 28 MCP specification removes the initialize/initialized handshake and the Mcp Session Id header, making every request self contained with protocol version and client capabilities carried in meta on each call. This breaking change requires client and server migration. Streamable HTTP requests in the 2026 07 28 spec require Mcp Method and Mcp Name headers so gateways can route and meter on headers without parsing JSON bodies. The specification replaces held open bidirectional SSE streams for server to client requests with Multi Round Trip Requests (MRTR), where the server returns input required and the client retries with answers attached in inputResponses. Responses from tools/list, prompts/list, resources/list, and resources/read carry ttlMs and cacheScope headers for client side caching. Tasks graduate from experimental core to the io.modelcontextprotocol/tasks extension, w…